The present invention relates to quick-detachable swivels for attaching a sling to a firearm and, in particular, to such swivels that have improved strength to withstand high stress generated by extreme pulling forces.
Quick-detachable swivels have been known in the art for some time. In general, such swivels have a loop at one end of a body for attachment to a sling, and a mounting pin that is receivable by a conventional mounting base or swivel stud attached to a firearm. An example of such a sling swivel is disclosed in Ives, U.S. Pat. No. 4,454,675. While the known sling swivels are functional, there has developed a need for swivels that are capable of withstanding extreme pull forces exerted on the sling. For example, it is desired to develop a swivel that is strong enough to allow a soldier in full gear to be pulled or carried by pulling on the sling attached to his weapon. Such a sling swivel should be capable of withstanding pull forces in excess of 500 pounds. In addition, the sling swivel must retain its quick-detachable capability, and must also be relatively lightweight.
However, such extreme pull forces induce severe stress in several portions of the sling swivel. The primary points of failure for sling swivels are the loop attached to the sling, and the shift/swing gate that prevents the mounting pin from being detached from the mounting base. Because the pull force is initially received by the loop, the loop may become deformed and fail when subjected to extreme pull forces. In addition, because the extreme pull forces may twist the sling swivel and induce torque within the shift/swing gate relative to the mounting pin, the pull forces may cause the shift/swing gate to become detached from the mounting pin and rotate from the closed to the open condition, thereby allowing the mounting pin to slide out of the bore of the swivel stud.
Two examples of sling swivels are disclosed in Ives, U.S. Pat. No. 4,454,675, and Ives, U.S. Pat. No. 5,067,267. In those swivels, the loop is fashioned from a piece of wire having a circular cross section that is bent to form the loop, so that the loop has curved sides. The two ends of the loop are then inserted into the body to attach the loop to the body. When such a swivel is subjected to extreme pull forces, the loop will either deform its shape, or pull completely apart from the body.
Another sling swivel, sold by Boonie Packer of Salem, Oreg., is made from injected molded metal so that the loop portion is integral with the body. However, the Boonie Packer loop has the same curved sides and circular cross-section as the loop of the swivels disclosed in the two Ives patents discussed above. Like those swivels, the loop of the Boonie Packer swivel also deforms when subjected to extreme pull forces.
Yet another sling swivel manufactured by Boonie Packer of Salem, Oreg., is formed by bending a wire having a rectangular cross-section to form a loop having curved outer portions, like that of the Boonie Packer injection molded sling swivel and the swivels disclosed in the two Ives patents. Instead of having a solid body, the two end portions of the wire extend in substantially straight lines away from the loop portion, with the mounting pin extending from one of the end portions. The wire loop of this swivel also fails when subjected to extreme pull forces.
Other sling swivels having a loop integral with the body are also known, but these are formed from plastic materials. An example of such a swivel is Shire U.S. Pat. No. 5,074,069. Such swivels are incapable of withstanding extreme pull forces.
Accordingly, what is still desired is a sling swivel that is quick-detachable, that is capable of withstanding extreme pull forces, that has a loop portion for attaching to a sling but that resists deformation when subjected to extreme pull forces, that has a shift/swing gate that resists opening when subjected to extreme stress, that is relatively light weight, and that is easily and cheaply manufactured.
The present invention overcomes the aforesaid drawbacks of the prior art and provides an improved quick-detachable sling swivel capable of withstanding extreme pull forces. The quick-detachable sling swivel of the present invention comprises a body having a first end and a tang located oppositely from the first end. The tang supports a mounting pin. A loop is attached to the first end of the body. An elongate plunger is mounted in the body and defines a plunger axis. The plunger is movable axially between first and second positions with respect to the body. A shift/swing gate is associated with the body through the plunger. The gate is rotatable when the plunger is in the second position, and the gate is capable of interconnecting with the tang when the plunger is in the first position. The swivel includes a locking mechanism for locking the plunger positively and selectively against movement from the first to the second position. The body and the loop are an integral member. The loop has a pair of opposed substantially parallel side members.
In another separate aspect of the invention, the gate has a wedge protruding toward the tang, the wedge having an upper surface that, when the gate is interconnected with the tang, opposes a flat lower surface of the body.
In yet another separate aspect of the invention, the swivel is capable of withstanding at least 500 lbs. of pull force.
The various aspects of the invention have one or more of the following advantages. The swivels are capable of withstanding extreme pull forces in excess of 500 lbs. without visible deformation. In particular, the substantially parallel side members of the loop are especially resistant to collapsing inwardly when subjected to extreme pull forces. The opposing surfaces of the gate and body also allow the swivels to resist opening when subjected to extreme stress. In addition, the injection molded metal swivels are also relatively light weight, and are easily and cheaply manufactured.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.